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The reaction of the N-phenylacetyl and N-phenylpropionyl derivatives of 1, 2, 3, 3a, 4, 5-hexahydro-6H-indol-6-one (3 and 10) toward nucleophilic species are described. Several examples demonstrating intermolecular and intramolecular reactions occurring on the two electrophilic sites of the enamino ketone function and potential utility of these reactions on the synthesis of heterocyclic compounds are presented. A possible mechanism to rationalize these products is also presented.

Under the suitably controlled conditions, the tertiary enaminones undergo intramolecular ring formation at Cα and Cγ to give 1-(2-bromo-4,5-methylenedioxybenzyl) tetra (or hexa)hydro-4(or 6)-oxoindoles which can serve as potential precursors to lycoranes.

Kurz skizziert werden die Synthese von α-Dihydro-caranon,a-Anhydrodihydrocaranin, 7-Lycoran, Hexahydroapoerysopindimethylether sowie die Photolyse von 1 ,2,3 ,3a,4,5-Hexahydro-1-(2-iod-4,5-dimethoxyphenylacetyl)-6H-indol-6-on.

Condensation of acetylacetone with anilines gives N-aryl derivatives of 4-aminopent-3-en-2-one. Similar treatment of benzoylacetone with various primary amines yields N-substituted 3-amino-1-phenylbut-2-en-1-ones. Both series of products with the cis-s-cis-enaminone structure behave as bidentate ligands for PdII to yield stable yellow complexes, the structures of which have been determined as bis(4-anilinopent-3-en-2-onato)- and bis(3-amino-1-phenylbut-2-en-1-onato)-complexes of palladium(II), respectively. To establish the structure of the complex in the solid state, X-ray crystal structure analyses have been carried out on bis[4-(2-bromoanilino)pent-3-en-2-onato]palladium(II). The crystals of the complex solvated by benzene are triclinic and belong to space group P, with cell dimensions a= 8.034(5), b= 11.613(5), c= 7.637(10)A, α= 98.67(5), β= 88.44(5), γ= 100.22(10)°, and Z= 1. The crystal structure has been solved using 2 951 reflections and refined to a final R value of 0.092. The Pd atom takes a square-planar co-ordination and the ligand molecules with the cis-s-cis-enaminone system form six-membered chelate rings with the metal.

Photocyclisation of 2,3,4,5-tetrahydro-N-(3,4-methylenedioxybenzoyl)indol-6(3aH)-one followed by stereoselective reduction with LiAlH4 provides a simple and new synthetic route to lycorine-type alkaloids.

1-Aza-3-(4-methoxyphenyl)bicyclo[4,3,0]nonan-4-one, key intermediate to (±)-ipalbidine, was conveniently synthesized by intramolecular cyclization of the N-formyIketone which was obtained via [3 + 2] cycloaddition reaction of the cyclic nitrone.

A novel synthesis of hexahydroapoerysopine dimethyl ether (11), by photolytic intramolecular arylation of the 6′-iodo- and 7-bromo-derivatives of 1,2,3,3a,4,5-hexahydro-N-(3,4-dimethoxyphenethyl)indol-6-one (6) and (8) to 2,3-dihydroapoerysopin-1(3aH)-one (9), followed by reduction with LiAlH4 to cis-2,3,3a,12c-tetrahydroapoerysopine (10) and then hydrogenation, is reported.

The N-(2-bromophenyl)-, N-(2-bromobenzyl)-, and N-(2-bromophenethyl)-derivatives (3) of 3-aminocyclohex-2-enones and 1,2,3,3a,4,5-hexahydro-1-(2-halogeno-4,5-methylenedioxybenzyl)indol-6-ones (10) and (11) underwent photochemical cyclisation to yield the five- to seven-membered heterocyclic compounds (5) and the 3,3a,4,5-tetrahydropyrrolo[3,2,1-de]phenanthridine-1,7-(2H)-dione (13), respectively.